Collapsible scaffold and lock therefor



COLLAPSIBLE SCAFFQLD AND LOCK THEREFOR Filed Oct. 15, 1951 2 Sheets-Sheet 1 INVENTORS HR, Be ne flfiBenavn ATTORNEYS June 22, 1954 H. R. BENSON ETAL COLLAPSIBLB SCAFFOLD AND LOCK THEREFOR 2 Sheets-$heet 2 Filed Oct. 15, 1951 INVENTORS.

HR fie naan R-HBenso n I BY 9M ATTORNEYS Patented June 22, 1954 OOLLAPSIBLE- SCAFFOLD AND, LOCK;

THEREFOR Howard R. Benson and Robert Hi Benson; Knoxville, Tenn.

Application October 15, 1951, Serial No. 251,328

1 Claim.

This invention relates to collapsible scaffolds.

In scaffolds of the collapsible type rigid upright end frames are provided and these frames are connected together by means of crossed bracing bars formed Of either angle or tubular bars. It is an object of thi invention to provide an improved releasable locking means for detachably securing the ends of the bracing bars to the end frames which will provide an improved safety factor whereby the scaffold assembly will be held against accidental collapsing after being set up.

Another object of this invention is to provide a locking means for the bracing bars of a scaffold which will gravitatingly fall into locked position so that the scaffold will thereby be held against collapsing.

With the above and other objects in View, our invention consists in the arrangement, combination and details of construction disclosed in the drawings and specification, and then more particularly pointed out in the appended claim.

In the drawings,

Figure 1 is a perspective view of a collapsible scaffold having bracing bars with locking means constructed according to an embodiment of this invention, for locking the bracing bars relative to the end frames,

Figure 2 is a fragmentary vertical section on an enlarged scale, showing the locking means for the bracing bars,

Figure 3 is a fragmentary sectional view taken on the line 3-3 of Figure 2,

Figure 4 is a fragmentary sectional view taken on the line 44 of Figure 2,

Figure 5 is a fragmentary side elevation showing the locking means in released position.

Referring to the drawings, the numerals l and II designate generally a pair of end frames which are adapted to be disposed in upright or vertical position and are connected together by means of crossed bracing bars and M which are pivotally connected together between the ends thereof by means of a pivot [3.

Each upright frame member ID is formed of vertically disposed pairs of bars l which are connected together by upper and lower connecting bars [6 and. I7 and angled bracing bars I8 are secured between the bars [6 and IT as shown in Figure 1.

In order to provide an improved means whereby the bracing bars l2 and I4 may releasably be locked at their ends to the upright bars I5 01 the vertical or end frames l0 and II, we have provided at the end of each bracing bar, as shown more clearly in Figures 2 to 5 inclusive, a locking plate H) which is pivotally mounted on a pivot member 20 which is carried by the end of a bracing bar such as bracing bar l2.

A keeper pin 2| is secured, as indicated at 22, to the upright bar l5, projecting inwardly therefrom, and the keeper pin 2| is provided with a pair of annular keeper grooves 23 and 24. The adjacent end of bracing bar 12 is formed with an opening 25 through which the keeper pin is adapted to engage, and the locking plate I9 is also formed with a pair of oppositely extending arcuate slots 21 and 28 which extend from the opening 26 and these slots 2'! and 28 are of a width such as to snugly engage the keeper pin within an annular groove or channel 23. The provision of the two keeper channels 23 and 24 provides a means whereby oppositely inclined bracing bars may be locked to a single keeper pin. In other words, where an additional end frame structure is to be used for enlarging the length of the scaffold, such additional frame or frames may be coupled to one of the two end frames It or H shown in Figure 1, by engaging the bracing bars of the additional frame structure to the keeper pins carried by the end frame members I0 and II.

In the use of this locking structure the end frames l0 and II are set up in substantially upright or vertical position and the ends of the bracing bars l2 and I4 are engaged with their associated keeper pins 2 I. During the mounting of the bracing bars on the keeper pins the locking plate I9 will be manually held in a released position which is the position shown in Figure 5. The bracing bar is inserted on the keeper pin and moved therealong until the bracing bar contacts with the adjacent upright frame bar l5. At this time the locking plate l9 will be disposed in registry with the inner keeper groove or channel 23 and locking plate l9 may be manually swung downwardly to the position shown in Figure 2. Where the locking plate I9 is relatively loosely mounted on the pivot pin. 20, the locking plat [9 will gravitatingly swing downwardly to its locked position.

While the scaffold frame herein disclosed has been shown as formed out of angle iron, this frame may also be formed out of tubing, and the locking structure may be readily adapted to the tubular frame in the same manner as for the angle frame.

We do not mean to confine ourselves to the exact details of construction herein disclosed, but claim all variations falling within the purview oi the appended claim,

What we claim is-- A collapsible scaffold comprising a pair of upright end frames, crossed pairs of bracing bars, each bracing bar having an opening adjacent each end thereof, pins fixedly carried by said end frames engageable through said openings, each pin having at least two longitudinally spaced annular grooves, and a locking plate pivotally carried by each bracing bar adjacent each end thereof, said plate having an arcuate slot havin a width substantially equal to the diameter of the pin at the bottom of said grooves, said plate also having an opening intersecting said slot at the mid-point between the ends of the latter and spaced a distance from said pivot equal to the distance of said opening in said bracing bar from 4 said pivot, said opening having a diameter substantially equal to the diameter of said pin, rocking of said plate in either direction to dispose said slot in said groove providing for releasably 5 locking said bracing bar to said frame in a selected one of two positions.

References Cited in the file of this patent UNITED STATES PATENTS 

